1. Field of the Invention
The present invention relates to a sensor device for use in a vehicle, various types of electronic devices, or the like.
2. Background Art
FIG. 5 is a block diagram of an inertial sensor, which is an example of a conventional sensor device. This sensor device includes driving circuits 1A and 1B, sensing element 2, detecting circuits 3A and 3B, processing circuits 4A and 4B, output circuits 5A and 5B, and failure diagnosing circuit 6. Each of driving circuits 1A and 1B outputs a drive signal. Driving circuits 1A and 1B supplies the drive signals to sensing element 2. Sensing element 2 includes an angular velocity detector and an acceleration detector. Each of detecting circuits 3A and 3B extracts a response signal from sensing element 2. Processing circuits 4A and 4B extract sense signals from the response signals extracted from detecting circuits 3A and 3B, respectively. Output circuits 5A and 5B output the sense signals extracted from processing circuits 4A and 4B, respectively. Failure diagnosing circuit 6 determines whether a part subjected to failure diagnosis is normal or abnormal, and outputs a failure detection signal that is based on the results. At least one of detecting circuits 3A and 3B, processing circuits 4A and 4B, and output circuits 5A and 5B is the part subjected to failure diagnosis.
However, such a conventional sensor device has a problem in improving the reliability thereof. In the above structure, the sense signal is not temporally correlated with the failure detection signal. Thus, the output sense signal cannot be determined precisely in an instant to be a signal in a normal state or a signal at the time of failure. Therefore, it is likely that an object to be controlled according to the output of this sensor device, such as a vehicle, is controlled using a sense signal at the time of failure.